Method and apparatus for storing liquified gases



Dec. 9, 1958 H. L. JoHNsToN METHOD AND APPARATUS FOR STORING LIQUIFIEDGASES Filed March 29, 1955 Nm. E

United States Patent METHD AND APPARATUS FR STORING LIQUIFIED GASESHerrick L. Johnston, Columbus,

L. Johnston, luc., Columbus, Ohio Ohio, assigner to Herrick Ohio, acorporation of This invention relates to storing volatile liquids havingboiling point temperatures materially below 273 Kelvin at atmosphericpressure and particularly to novel method and apparatus whereby theliquid may be contained for indenite storage on a no-loss basis.

In general, the present invention provides method and apparatus for thesafe and efficient storage of expensive, toxic, corrosive, ilammable orotherwise hazardous liquied gas having a boiling point below 273 Kelvinutilizing a colder radiation shield containing a liquid having a boilingpoint below the boiling point of the liquid being stored. The liquidutilized in the colder radiation shield may be less expensive or lesstoxic, or less corrosive, or less flammable than the liquid beingstored. Moreover, it can be inert or unreactive with the stored liquid,thus providing an eliicient and safe means of storing a liquied gas onan indenite no-loss storage basis. ln practicing the present invention,not only can the stored liquid be contained for indefinite storage, butit can be safely contained for shipment via the various conventionalmodes of transportation.

As an example of one aspect of the present invention7 liquid uorine canbe safely and eiciently stored and transported utilizing liquid nitrogenas a colder radiation shield according to the teachings of the presentinvention.

It is therefore an object of the present invention to provide method andapparatus for storing a volatile liquid of the type described wherein anovel colder radiation shield is utilized to shield the stored liquidfrom radiation from the environment.

It is another object of the present invention to provide method andapparatus for storing a volatile liquid of the type described by meansof a novel radiation shield comprising a contained liquid having aboiling point below the boiling point of the liquid being stored. Withsuch arrangement, said second liquid not only isolates the stored liquidfrom radiation from the environment, but also permits heat transfer onlyfrom the stored liquid to the second liquid whereby the stored liquid iscontained on a no-loss basis.

lt is another object of the present invention to provide method andapparatus for storing a volatile liquid of the type described utilizinga novel radiation shield interposed between the stored liquid and theenvironment, said radiation shield being adapted to control thetemperatures of the stored liquid by effecting controlled heat transferfrom the stored liquid to said radiation shield whereby said storedliquid canbe maintained at a predetermined storage temperature.

It is another object of the present invention to provide method andapparatus for storing a volatile liquid of the type described whichutilizes a novel radiation shield interposed between the stored liquidand the environment, and which includes means for varying the rate ofheat transfer from the stored liquid to said radiation shield wherebythe temperature of the stored liquid can be eliiciently and safelyvaried.

It is another object'of the present invention to provide method andapparatus for storing a volatile liquid of the type described utilizinga novel radiation shield interposed between the stored liquid and theenvironment and which provides means for effecting heat transfer fromthe stored liquid to said radiation shield whereby the stored liquid canbe maintained at a predetermined subcooled temperature notwithstandingthe occurrence of a certain amount of heat transfer from the environmentto the liquid being stored.

It is another object of the present invention to provide method andapparatus for storing a liquied gas of the type described whereby theliquid being stored can be delivered to the storage means at boilingpoint temperature, yet due to the novel radiation shield utilized in thepresent invention, the stored liquid can be eiciently and safelysubcooled subsequent to delivery thereof to the storage means. i

It is another object of the present invention to provide method andapparatus for storing a liquied gas of the type described whicheliminates boil-olf, and hence loss of the liquid being stored, withoutthe need for a recondensor apparatus or an external refrigeration cycle.

It is another object of the present invention to provide method andapparatus for storing a volatile liquid of the type described wherebythe liquid is maintained in a subcooled condition which permits thepumping of same without the need of pressurizing the liquid or elevatingthe containing vessel above pump suction to effect subcooling.

Further objects `and advantages of the present invention will beapparent from the following description, reference being had to theaccompanying drawing wherein a preferred form of embodiment is shown.

In the drawings:

Figure l is a schematic view of a storage means and vassociated controlapparatus arranged according to one aspect of the present invention andadapted for practicing the method thereof. Figs. l and 2 are sectionalviews, taken on lines l-i of Fig. 2 and 2-2 of Fig. l, respectively, andlooking in the direction of the arrows.

Referring next to the drawing, an apparatus for practicing the presentinvention is schematically illustrated in Figure 1 with such apparatusincluding a storage means indicated generally at tti. Storage means 1i)includes an outer jacket l?, which surrounds an insulating space 13.'insulating space EL3 may be in the form of a vacuum chamber or it maybe formed as a vacuum chamber containing insulating material such astine particles of low conductivity and high reliectivity. A vacuum canbe maintained in the insulating space i3 by connecting such space with asource of vacuum Zti by means of the lines 16 and 17. A valve il@ islocated along line 17 to control and maintain the vacuum in insulatingspace 13.

Reference is next made to a radiation shield structtue indicatedgenerally at 22. Radiation shield 22 is supported within the outerjacket 12 by a plurality of structural members 2li, 2S, 2o and 27, whichextend between the inner wall of the outer jacket l2 and an outer wall30 of the radiation shield. For example, structural member 24 has oneend thereof secured to the outer jacket l2 at 2S, and the other endthereof secured to the radiation shield Z2 at 29.

Radiation shield 22 further includes an inner wall 32 `and end walls 33and 34 which form a sealed chamber 36. At this point it should be notedthat the chamber 36 of the radiation shield substantially surrounds asecond insulating means indicated generally at 38 and provided with anouter shell 42. Insulating means 38 in turn surrounds a container 4t)which directly contains the liquid being stored.

Referring further to the inner container 40, such container is supportedin spaced relationship with the radiation shield 22 and wall means 42 bymeans of a plurality of structural members such as are exemplied by themembers indicated at 4d, 45, 4l 6 and 47. For example, structural memberid has one end thereof secured to the inner side of wall 32 at 49, andthe other end thereof Secured to the outer side of wall lli at 5d.

Since the inner container lll is supported by the radiation shieldstructure 22, and since the radiation shield structure is suspendedwithin the outer sheil 't understood that the inner container iii 1substantially rigid suspension relative to tne surrounding structure ofthe storage means.

The inner container can be iilled and drained of th liquid to be storedby means of a line ed and valve The inner container is further providedwith s pressure release valve 63 which is connected to the innercontainer by means of a line 6d.

Reference is again made to the radiation shield 22 and particularly tochamber 36 thereof which is adapted to receive and store a duid in theliquid state. A. fluid having a boiling point lower than the boilingpoint of the stored liquid is utilized to provide a radiation shieldwhich is maintained colder than the liquid being stored. A line 6a andvalve 67 serve to ll and drain the colder liquid carried in chamber 36,and a safety pressure relief control valve 7i", is connected with thechamber 36 by means of a line 7l.

Reference is next made to the inner insulating means 38 which includes achamber 75 in surrounding relationship with the inner container 4d.Chamber 75 is connected to the source of vacuum Ztl by means of a line77 which extends from chamber 75 to the vacuum line i6. A valve 78 isinterposed along the line so that the chamber 75 can be selectivelyisolated from the vacuum source 2i). A pressurization source d@ isconnected to chamber 75 by lines Slt and 77, and a valve 83 is providedfor controlling the rate of gas flow from the pressurization sourcetitl, or for isolating such source from 4 the chamber 75. Hence it isseen that the pressure in the chamber 75 can be readily varied by meansof the valve 73, which is interposed between chamber 75 and the vacuumsource 20, and by means of the valve d3 which is interposed betweenchamber 75 and the pressurization source 8u.

ln addition to the above described vacuum and pressurization arrangementfor chamber 75, it will be understood that chamber 75 can also bearranged to contain insulating materials such as tine particles of lowthermal conductivity and high reiiectivity.

ln operation, radiation shield liquid is introduced into the chamber 3Sof the radiation shield through the till line 66. The liquid to bestored is transferred to the inner container 4) by means of the fillline oil. With this arrangement, the radiation shield liquid in thechamber 36 substantially surrounds the stored liquid in the innercontainer itl and hence the radiation shield liquid is inter-posedbetween the stored liquid and the ambient telnperature of theenvironment surrounding the outer shell of the storing means. At thispoint, it will be understood that the colder radiation shield 22 acceptsradiation heat from the surrounding environment and thereby prevents theradiation heat from passing to the stored liquid in the inner containerdi?. This must occur since the radiation shield liquid in the chamber 36is colder, according to the present invention, than the temperature ofthe stored liquid in the inner container dit. Since heat can betransferred only from the warmer substance to the colder substance, itwill be understood that heat can only move outwardly from the innercontainer to the radiation shield 22 and hence the stored liquid canonly become colder.

At this point it should be noted that the structural members 44, d5, 46and 47 extend between the inner container itl and the radiation shield22 and form heat conducting paths whereby a certain amount of heat iscontinuously conducted outwardly from the warmer stored liquid to thecolder radiation shield. Since the rate of heat conduction is a functionof the physical characteristics of the support members 44, 45, 46 and47, a continuous outward conduction of heat from the stored liquid canbe effected at a predetermined rate by the appropriate structural designand selection of material for such structural members.

It will be understood that it is advantageous to control the temperatureof the stored liquid in the inner container in order to eficientlysupply the liquid with necessary refrigeration, or in other instances7to subcool the liquid after it has been placed in the inner containerlill, or, in still other instances, to maintain the stored liquid in asubcooled condition. According to the present invention, the temperatureof the stored liquid can be controlled by controlling the rate at whichthe stored liquid gives up heat to the colder radiation shield 22. Toeffect such controlled heat transfer, the present apparatus may beadapted to readily and precisely vary the rate at which heat istransferred outwardly through the insulating space 75 by varying thepressure therein by means of the control valves 83 and 78 in the mannerpreviously described. Since all heat passing from the stored liquid tothe radiation shield must pass through the gas contained in insulatingspace 75, it will be understood that the rate of heat transfer will be afunction of the molecular concentration of the gas and hence a functionof pressure of the gas in insulating space 75.

When it is desired to lower the temperature of the stored liquid, valve83 to the pressurization source 80 can be opened and valve 78 to thevacuum source can be closed to produce an increase in the gas pressurein chamber 75. The rate of heat transfer from the stored liquid to thecolder radiation shield 22 will then increase and valve 83 can bemaintained open until the temperature of the stored liquid has droppedto the desired valve.

lf an increase in temperature of the stored liquid is desired, valve 78to the Vacuum source 20 can be opened and valve 83 to the pressurizationsource 80 can be closed to effect a rapid reduction in pressure ininsulating space 75 with a resulting decrease in the rate of heattransfer from the stored liquid to the colder radiation shield 22. Inthis case the design of the vessel would incorporate a heat leak to thestored fluid, through piping 60 and 64 and other means, greater than theheat loss through the suspension members to the radiation shield. Thusthe present method and apparatus are readily adaptable to meet variousconditions encountered in service.

As an illustrative example of one aspect of the present invention,liquid fluorine can be safely and efficiently stored on a rio-loss basisby using nitrogen as a radiation shield liquid according to the presentteachings. Liquid fluorine has a boiling point of C. and a freezingpoint of 223 C., while nitrogen has a boiling point of -l95.8 C. and afreezing point of -209.8 C. In this particular example, both the boilingpoint and freezing point of the radiation shield liquid are between theboiling point and freezing point of the stored liquid and hence the twoliquids could be maintained in controlled heat transfer relationship andwithout freezing the stored liquid. Due to the presence of the colderradiation shield of the present invention, however, heat can transferonly from the iluorine to the nitrogen and the fluorine can only getcolder. Hence, with the particular example of iluorine and nitrogen, theaspect of controlling the rate of heat transfer through the intermediateinsulating space '75, by controlling the pressure therein, need beutilized only when it is desired to provide control for the temperatureof the stored fluorine as would be the case when it is desired tosubcool the fluorine to a certain predetermined temperature after it hasbeen introduced into the storage means.

As another aspect of the present invention, it will be understood that aradiation shield liquid can be utilized having a boiling pointtemperature below the freezing point temperature of the liquid beingstored. In such instance, when the heat loss through the structuralmembers 44, 45, 46, 47 of the suspension system is less than the heatleak inwardly along the pressure relief, ll and drain piping 64 and 60,and other means, then the control system `tor varying the rate of heattransfer through the intermediate insulating space 75 is required tocontrol the temperature or amount 4of subcooling of the stored liquid.Such temperature control can be eitected byraising and lowering thepressure of the gas in insulating space 75 to raise and lower the rateof heat transfer from the stored liquid to the radiation shield 22.

As still another aspect of the present invention, the temperature of thestored liquid can be controlled by varying the pressure, and hence thecorresponding temperature, of the liquid contained in the radiationshield 22. To etect such control of the pressure of the radiation shieldliquid, a variable pressurization means, schematically illustrated at85, can be connected to the line 7li by means of a line 37 and a valve88. In eiecting control of the temperature of the stored liquid incontainer 4t), by means of the variable'pressurization means 85, thevalve 88 is opened to connect the radiation shield liquid with thevariable pressurization means. When it is desired to vary thetemperature of the stored liquid, the variable pressurization means isadjusted to produce a desired corresponding variation in the temperatureof radiation shield liquid. Such variation in the temperature of theradiation shield liquid will produce a corresponding change in the rateof heat transfer from the stored liquid to the radiation shield liquid.Hence the temperature of the stored liquid is made warmer or colder byvarying the effect of the variable pressurization means on the radiationshield liquid.

In summary, it is seen that the present invention provides a safe andefficient way for storing dangerous or expensive liquiiied gases on ano-loss basis by use of a novel radiation shield which substantiallycompletely isolates the stored liquid from heat radiation trom theenvironment, and which permits heat transfer, between the stored liquidand the radiation shield, only in the direction of the radiation shieldand away from the liquid being stored. Moreover, the method andapparatus of the present invention is readily adaptable to provideconvenient and precise control of the temperature of the liquid beingstored. Hence the system becomes versatile in its adaptation to thevarious applications to which it may be employed.

While the form of embodiment of the present invention as disclosedherein constitutes a preferred form, it is to be understood that otherforms might be adopted, all coming within the scope of the claims whichfollow.

' I claim:

l. An apparatus for no-loss storage of volatile liquid iluorine having aboiling point materially 'bel-ow 273 K. at atmospheric pressurecomprising, in combination: a storage container for the liquid beingstored, an insulating jacket in spaced surrounding relationship withsaid storage container, a cold radiation shield interposed 'between saidstorage container and said insulating jacket, and means for supplying adiEerent volatile liquid which contacts said shield continuously tomaintain it cold, said radiation shield being immediately separated fromsaid storage container by an insulating space evacuated belowatmospheric pressure.

2. An apparatus for no-loss storage of volatile liquid lluorine having aboiling point material below 273 K. at atmospheric pressure comprising,in combination: a first container for the liquid being stored, aninsulating jacket in spaced surrounding relationship with said rstcontainer, a cold radiation shield interposed between said iirstcontainer and said insulating jacket, said radiation shield comprising asecond container containing a different volatile liquid and immediatelyseparated from said rst container by an insulating space evacuated belowatmospheric pressure, having a boiling point lower than the boilingpoint of the stored liquid.

3. An apparatus for no-loss storage of volatile liquid lluorine having aboiling point temperature materially below 273 K. comprising, incombination: a storage container for the liquid being stored; aninsulating jacket in spaced surrounding relationship with said lirstcontainer; a cold radiation shield formed to contain a differentvolatile liquid, said radiation shield being interposed between saidstorage container and said insulating jacket and spaced from saidjacket; a gas-containing insulation chamber evacuated below atmosphericpressure and immediately disposed between said shield and said storagecontainer; and pressure-control means including a conduit incommunication with said chamber forvarying the effectiveness of saidinsulation by varying the gas pressure in said chamber.

4. An apparatus for no-loss storage of volatile liquid uorine having aboiling point temperature materially below 273 K. comprising, incombination: a storage container for the liquid being stored; aninsulating jacket in -spaced surrounding relationship with said firstcontainer; a cold radiation shield formed to contain a diterent volatileliquid, said radiation shield being interposed between said storagecontainer and said insulating jacket and spaced from said jacket, achamber immediately dis posed between said shield and said storagecontainer, and vacuum-producing means including a conduit incommunication with said chambers, for varying the degree of vacuum insaid chamber.

5. An apparatus for noloss storage of volatile liquid uorine having aboiling point temperature materially below 273 K. at atmosphericpressure, comprising, in combination: a storage container for the liquid'being stored; an insulating jacket in spaced surrounding relationshipwith said container; a cold-radiation shield formed to contain adifferent volatile liquid and interposed between said storage containerand said insulating jacket; insulation evacuated below atmosphericpressure and immediately disposed between said storage container andshield; and means for varying the pressure and corresponding temperatureof said ditterent liquid whereby the rate of heat transfer from saidstored liquid to said radiation shield can be predetermined.

6. In no-loss storage of liquid iluorine in apparatus having an exteriorjacket and an interior storage container, the method of controlling thetemperature of the stored liquid in the container, which methodcomprises interposing between said stored uorine and the jacket aquantity of a different liquid having a boiling point below the boilingpoint of the stored iluorine; maintaining said diierent liquid in aliquefied state to provide a radiation shield; vacuum-insulating thestored fluorine from said second liquid; and varying the magnitude ofthe insulating effect whereby control of the temperature of said storediluorine is effected.

7. In no-loss storage of liquid fluorine in apparatus having an exteriorjacket and an interior storage container, the method of controlling thetemperature of the stored fluorine in a container which method comprisesinterposing between said stored fluorine and the jacket a quantity ofliquid having a boiling point below the boiling point of the storeduorine; maintaining the last-mentioned liquid in a liquerled state toprovide a colder radiation shield; interposing a vacuum between saidstored lluorine and the shielding liquid; and varying the amount of thevacuum to eiect control of the temperature of the liquid iluorine.

8. In no-loss storage of volatile liquid luorine having a boiling pointtemperature materially below 273 K. at atmospheric pressure in apparatushaving an exterior jacket and an interior storage container, the methodcomprising: interposing between the stored liquid and the jacket aquantity of radiation-shielding liquid; vacuum said diierent volatileliquid insulating the stored and shielding liquids from each other; anddetermining the pressure and corresponding temperature conditions of theradiation shield liquid whereby the rate of heat transfer from saidstored liquid to said radiation shield can be controlled withinpredetermined limits.

9. An apparatus for no-loss storage of liquid fluorine, having a boilingpoint temperature materially below 273 K. at atmospheric pressure,comprising, in combination, container means for the liquid iluorine; ajacket surrounding the container means; and means forming anitrogen-cooled radiation shield colder than the boiling point andwarmer than the melting point of said liquid being stored, saidradiation shield being interposed between said container and the jacket,and spaced from the container means by a chamber, which is evacuatedbelow atmospheric pressure.

References Cited in the le of this patent UNITED STATES PATENTS 646,459Place Apr. 3, 1900 797,577 I-Ieylandt Aug. 22, 1905 1,515,165 OswaldNov. 11, 1924 1,680,873 Lucas-Girardville 'Aug 14, 1928 2,148,109 Danaet al Feb. 21, 1939 2,195,077 Brown Mar. 26, 1940 2,229,437 Birdsall`lan. 21, 1941 2,269,172 Birdsall Ian. 6, 1942 2,396,459 Dana Mar. 12,1946 2,550,040 Clar Apr. 24, 1951 UNITED STATES PATENT OFFICECERTIFICATE OF `CORRECTION Patent Noll 2,863,297 December 9, 1958Herrick L. Johnston It is herebr certified that error appears intheprinted specification of the above "numbered patent requiringcorrection and that the said Letters Patent should read as correctedbelow.

for ndesired valve" read desired value column Column 4, line 37,-

; c'olumno, line 30, for

signed and Sealed this 19ml day of May 1959.

( SEAL) Attest:

KARL H. AXLINE ROBERT C. WATSON Attesting Ocer Commissioner of Patents

9. AN APPARATUS FOR NO-LOSS STORAGE OF LIQUID FLUORINE, HAVING A BOILING POINT TEMPERATURE MATERIALLY BELOW 273*K. AT ATMOSPHERIC PRESSURE, COMPRISING, IN COMBINATION, CONTAINER MEANS FOR THE LIQUID FLUORINE; A JACKET SURROUNDING THE CONTAINER MEANS; AND MEANS FORMING A NITROGEN-COOLED RADIATION SHIELD COLDER THAN THE BOILING POINT AND WARMER THAN THE MELTING POINT OF SAID LIQUID BEING STORED, SAID RADIATION SHIELD BEING INTERPOSED BETWEEN SAID CONTAINER AND THE JACKET, AND SPACED FROM THE CONTAINER MEANS BY A CHAMBER, WHICH IS EVACUATED BELOW ATMOSPHERIC PRESSURE. 